Process for the dyeing of fibre material

ABSTRACT

An improved process for dyeing of diverse fibre material, especially textile fibres, by applying to the fibre material at a temperature below the absorption temperature of the dyestuffs a concentrated aqueous dye liquor and with a goods to liquor ratio of 1:1.5 to 1:4, the said aqueous dye liquor containing at least one dyestuff which, in the case of the substrate to be dyed, has affinity to the fibres and which is either soluble or dispersible in water and 0.2 to 10 g/l, preferably 2 to 5 g/l, of a non-foaming anionic dispersing agent from the class of aromatic sulphonic acids or the water-soluble salts thereof, and finishing of the dyeing by means of a heat treatment, e.g. introduction of saturated steam, superheated steam or hot air, preferably by heating from without, at temperatures of 95° to 140° C.

This is a continuation of application Ser. No. 551,934, filed Feb. 24,1975, now abandoned, which is a continuation of application Ser. No.302,697, filed Nov. 1, 1972, now abandoned.

The present invention relates to a process for the dyeing of fibrematerial in concentrated dye liquors with water-soluble orwater-dispersible dyestuffs, as well as to the fibre material dyed bythe new process.

Processes are known which consist of the continuous dyeing of voluminoustextile webs in concentrated dye liquors by the feeding of the websthrough a trough filled with dye liquor, or by the impregnation of thesaid material by means of an overflow, with dye liquor absorptions ofca. 250 to 300% being obtained; and subsequently the fixing of thedyestuff by, for example, steaming with saturated steam. These processesare limited, however, to the dyeing of voluminous webs, particularlycarpets.

Moreover, the process has already been suggested wherein fibre materialis dyed in concentrated dye liquors containing the dyestuff and at leastone foam-forming compound, dyeing being effected by means of a stablemicrofoam. For example, the material to be dyed is sprayed with dyeliquor, and fed into a drum dyeing machine, whereupon an intense foam isproduced by a tumbling action, the dyestuff being then fixed by a heattreatment consisting, for example, of the introduction of saturatedsteam or hot air. But this process too has disadvantages, one particulardisadvantage being that relatively large amounts of foam-formingcompounds are required, with the removal of these from the dyed materialnecessitating the application of several washing operations.Furthermore, dyeing in the presence of a stable microfoam can beperformed only in a quite specific type of equipment.

A process has now been found which renders possible, in a simple mannerand with avoidance of the mentioned difficulties and disadvantages, theobtainment on diverse fibre materials, preferably textile fibres, ofexcellent dyeings in concentrated dye liquors. This process comprisesthe application to the fibre material of an aqueous dye liquor at atemperature below the absorption temperature of the dyestuffs and with agoods to liquor ratio of 1:1.5 to 1:4, the said aqueous dye liquorcontaining at least one dyestuff which, in the case of the substrate tobe dyed, has affinity to the fibres, and which is either soluble ordispersible in water, and 0.2 to 10 g/l, preferably 2 to 5 g/l, of anon-foaming anionic dispersing agent from the class of aromaticsulphonic acids or water-soluble salts thereof, and the finishing of thedyeing by means of a heat treatment.

Suitable water-soluble dyestuffs having affinity to fibres orwater-dispersible dyestuffs, applicable according to the invention, arethe same organic dyestuffs as are normally used in textile dyeing forthe dyeing of fibre materials, particularly textile fibres, from anaqueous dye liquor. Depending on the substrate to be dyed, suitabledyestuffs are water-soluble anionic or cationic dyestuffs, or dispersiondyestuffs.

The dyestuffs usable according to the invention can belong to the mostdiverse classes of dyestuffs. These are, in particular, mono-, dis- orpolyazo dyestuffs, formazan, anthraquinone, nitro, methine, styryl,azastyryl or phthalocyanine dyestuffs.

With regard to the water-soluble anionic dyestuffs these are, inparticular, the alkali metal salts or ammonium salts of the dyestuffsknown as acid wool dyestuffs, of the reactive dyestuffs, or of thesubstantive cotton dyestuffs of the azo, anthraquinone andphthalocyanine series. Suitable azo dyestuffs are preferably metal-freemono- and disazo dyestuffs containing one or more sulphonic acid groups,heavy-metal-containing, particularly copper-, chromium-, nickel- orcobalt-containing, monoazo, disazo and formazan dyestuffs, andmetallised dyestuffs containing bound to one metal atom 2 molecules ofazo dyestuff. Anthraquinone dyestuffs to be given particular mention are1-amino-4-arylamino-anthraquinone-2-sulphonic acids, and in the case ofphthalocyanine dyestuffs, particularly sulphated copper phthalocyaninesor phthalocyaninearylamides.

As reactive dyestuffs containing sulpho groups mention may be made ofwater-soluble dyestuffs of the azo, anthraquinone and phthalocyanineseries containing at least one fibre-reactive group, e.g. amonochlorotriazinyl, dichlorotriazinyl, dichloroquinoxalinyl,trichloropyrimidinyl, difluorochloropyrimidinyl, α-bromoacrylamide groupor the β-oxyethylsulphuric acid ester group.

In the case of the water-soluble cationic dyestuffs, these are the usualsalts and metal halide double salts, e.g. zinc chloride double salts, ofthe known cationic dyestuffs, especially the methine, azomethine, or azodyestuffs which contain the indolinium, pyrazolium, imidazolium,triazolium, tetrazolium, oxdiazolium, thiodiazolium, oxazolium,thiazolium, pyridinium, pyrimidinium or pyrazinium ring. Also suitableare cationic dyestuffs of the diphenylmethane, triphenylmethane, oxazineand thiazine series, and, finally, also dye salts of the arylazo andanthraquinone series with an external onium group, e.g. an externalcyclammonium group or alkylammonium group.

Concerning the dispersion dyestuffs, these are especially azo dyestuffs,as well as anthraquinone, nitro, methine, styryl, azostyryl,naphthoperinone, quinophthalone or naphthoquinoneimine dyestuffs. Thesedifficultly water-soluble dyestuffs form in the finely-ground condition,with the aid of dispersing agents, very fine aqueous suspensions.

The process according to the invention is suitable also for the opticalbrightening of undyed textile materials with dispersion brighteners, andparticularly with water-soluble anionic and cationic opticalbrighteners. These can belong to any desired classes of brighteners.They are, in particular, stilbene compounds, coumarins, benzocoumarins,pyrazines, pyrazolines, oxazines, dibenzoxazolyl or dibenzimidazolylcompounds, as well as naphthalic acid imides.

The amounts in which the dyestuffs are used in the dye baths can vary,depending on the desired depth of colour, within wide limits; ingeneral, amounts of 0.001 to 10 percent by weight, relative to thematerial to be dyed, of one or more dyestuffs have proved advantageous.

The cationic dyestuffs are employed, for example, for the dyeing offibre materials made from polyacrylonitrile, modified syntheticpolyesters or polyamides, cellulose-21/2-acetate, cellulose triacetateand silk; the anionic acid dyestuffs, metal-complex dyestuffs,substantive and reactive dyestuffs for the dyeing of fibre materialsmade from natural or regenerated cellulose, such as cotton, spun rayonand Rayon, natural polyamides such as wool and silk, syntheticpolyamides such as polyhexamethylenediaminoadipate, poly-ε-caprolactamor poly-ω-aminoundecanoic acid, and polyurethanes; and the dispersiondyestuffs for the dyeing of fibre materials made from syntheticpolyesters such as polyethylene glycol terephthalate,polycyclohexanedimethyleneterephthalate, cellulose triacetate,polyacrylonitrile, synthetic polyamides, polyurethanes and polyolefins.

The process according to the invention has proved particularlysatisfactory for the dyeing of mixtures of these fibre types with amixture of the dyestuffs suitable for the substrates to be dyed; forexample, mixtures of polyacrylonitrile/spun rayon, polyester/cotton,polyester/spun rayon, polyamide/spun rayon, polyamide/cotton,cellulose-21/2-acetate/spun rayon, cellulosetriacetate/spun rayon,polyacrylonitrile/polyester, and especially polyester/wool.

The fibre materials can be in the most diverse stages of processing;e.g., they may be in the form of fabrics, knitwear, yarns, ready-madearticles, knitted goods, fibre fleece materials, textile floor coveringssuch as woven, tufted or felted carpets.

Non-foaming anionic dispersing agents usable according to the inventionare aromatic sulphonic acids, thus e.g., benzene or naphthalenemonosulphonic acids or their water-soluble salts. Alkylbenzene oralkylnaphthalene sulphonic acids having a straight or branched chainalkyl radical containing at most 4 carbon atoms orcycloalkyl-substituted benzene sulphonic acids, e.g. methyl, ethyl,propyl, isopropyl or tert.butyl benzene sulphonic acid, dimethylbenzenesulphonic acid, 1-methyl- or 1-isopropyl-naphthalene-2-sulphonic acid,and mainly tetrahydronaphthalene sulphonic acids, preferablyβ-tetrahydronaphthalene sulphonic acid, or a mixture of α- andβ-tetrahydronaphthalene sulphonic acid, are particularly effective.

Preferred because they produce particularly good colour yields arenon-foaming water-soluble condensation products from 1 to 2 equivalentsof formaldehyde or compounds giving off formaldehyde such astrioxymethylene and 2 equivalents of an aryl sulphonic acid or a mixtureof such aryl sulphonic acids usable according to the invention. They areobtained, for example, by one of the processes described in German Pat.No. 292,531. Examples of aryl sulphonic acids are, in particular, arylmonosulphonic acids such as benzene, toluene, xylene, naphthalene,methyl naphthalene, tetrahydronaphthalene or diphenyl-naphthyl-methanemono sulphonic acid. The best results from this class of compounds areattained with condensation products from 2 equivalents oftetrahydronaphthalene sulphonic acid, xylene sulphonic acid, and,particularly, naphthalene sulphonic acid or diphenyl-naphthylmethanesulphonic acid or mixtures of toluene or xylene sulphonic acid andnaphthalene sulphonic acid and 1 to 2, preferably 1.1 to 1.7 equivalentsof formaldehyde.

Particularly suitable are tetrahydronaphthalene sulphonic acid andespecially condensation products from 2 equivalents of naphthalenesulphonic acid and 1.4 equivalents of formaldehyde or from 2 equivalentsof diphenyl-naphthylmethane sulphonic acid and 1.1 to 1.2 equivalents offormaldehyde, e.g. dinaphthyl-methane disulphonic acids, such as thedisodium salt of di-(6-sulphonaphthyl-2)-methane.

These sulphonic acids are generally used in the form of theirwater-soluble salts, particularly their alkali metal or ammonium salts,but also their alkyl and hydroxyalkyl ammonium salts, such as lithium,potassium, sodium, ammonium, β-hydroxyethyl- orbis-(β-hydroxyethyl)-ammonium salts.

If necessary, the dyestuff liquor can contain further components such asacids, especially an organic, lower aliphatic monocarboxylic acid, e.g.formic or acetic acid; sodium hydroxide; salts, such as ammoniumsulphate, sodium sulphate, sodium carbonate or sodium acetate; wettingagents, such as nonylphenoldecaethylene glycol ether or sodiumdioctylsulphosuccinate; and/or carriers, e.g. based on o-phenylphenol,trichlorobenzene or diphenyl.

For the preparation of dye liquors, it is advantageous to commence withaqueous dyestuff solutions or dyestuff dispersion, and to then add tothese the suitable aromatic sulphonic acids defined.

The process according to the invention is preferably performed inclosed, optionally pressure-tight containers, e.g. in circulationequipment such as cheese dyeing machines or beam dyeing machines, jetmachines, winch dyeing machines, drum dyeing machines, open vats, or inpaddle- or jig-dyeing machines. The process can be carried out, forexample, as follows: The dye liquor and the material to be dyed aretransferred, with a goods to liquor ratio of 1:1.5 to 1:4, preferably1:1.5 to 1:2.5, or the material impregnated with the given goods toliquor ratio or advantageously sprayed, at a temperature below theabsorption temperature of the dyestuffs, advantageously at 20° to 40°C., to the container; the dye liquor is then evenly distributed on thefibre material, below the absorption temperature of the dyestuffs,optionally by mechanical movement; and the temperature of the dye bathsubsequently raised, by the introduction of saturated steam, superheatedsteam or hot air, advantageously however by heating from without, within15 to 30 minutes to 95° to 140° C., advantageously to 98° to 105° C.;and this temperature maintained for ca. 15 to 120 minutes,advantageously for 20 to 45 minutes, until the dye liquor is exhausted.The dye bath is then cooled and the dyed material removed from the bath;the bulk of surplus dye liquor is separated from the material bysqueezing, and the dyed fibre material, optionally after rinsing withwarm water, dried. By virtue of the high degree of bath exhaustion andthe small amounts of anionic dispersing agent, a subsequent cleansing ofthe dyed material is in most cases unnecessary.

Compared with known processes, the process according to the inventionhas noticeable advantages. The main advantages are that the dyestuffsare practically completely absorbed, that only small migration of thedyestuffs occurs, and that, within shorter dyeing times than usual,deeply coloured, even and non-streaky dyeings well dyed throughout areobtained. According to the present invention, deeply coloured dyeingsare obtained with extremely small amounts of water, and hence withpractically no accumulation of contaminated water, and without dyeingbeing performed in the presence of a stable microfoam, the obtaineddyeings being to a great extent free from sandwich effects.

The following examples serve to illustrate the invention. Temperaturesare expressed in degrees Centigrade.

EXAMPLE 1

An amount of 0.9 g of the dyestuff of the formula ##STR1## is dissolvedin 90 ml of hot water; additions are then made to the solution of 0.5 gof the disodium salt of di-(6-sulphonaphthyl-2)-methane and 0.2 ml ofacetic acid (80%), and the whole made up by the addition of water to 100ml. After cooling to room temperature, the dyestuff solution istransferred together with 66 g of polyamide-6.6-tricot in the rolled-upstate, to a metal container such as is employed for the dye baths of theequipment of the firm Callebaut de Blicquy, Brussels; the container isthereupon sealed and thoroughly shaken. The container is then maintainedin continuous movement in the dyeing apparatus in the usual manner; thebath temperature is raised within 15 minutes from 20° to 100°, and thenheld at this temperature for 30 minutes. After cooling, the dyed fabricis removed, and then squeezed out to leave as little moisture aspossible in the material; it is subsequently rinsed by heating withwater, with a goods to liquor ratio of 1:2, in the above describedcontainer for 5 minutes, and finally dried.

An even, non-streaky, brilliant red dyeing is obtained which isexcellently dyed throughout, and which has very good fastness to wetprocessing and to light.

EXAMPLE 2

If, instead of the dyestuff given in Example 1, 1.5 g of the1:2-chromium complex of the dyestuff of the formula ##STR2## is used,and instead of 66.6 g of polyamide-6.6-tricot 66.6 g of wool flannel,the procedure being otherwise as described in Example 1, then adark-grey even wool dyeing is obtained well dyed throughout andpossessing good fastness to wet processing and to light. The smallamount of dye liquor remaining after dyeing is colourless.

If, instead of 0.5 g of the disodium salt ofdi-(6-sulphonaphthyl-2)-methane in the above example, 0.5 g of thesodium salt of tetrahydronaphthalene sulphonic acid, 0.2 g of a mixtureof the β-hydroxyethylammonium salt of α- and β-tetrahydronaphthalenesulphonic acids or 0.3 g of the condensation product of 2 molsdiphenyl-naphthyl-methane sulphonic acid and 1.2 mols of formaldehyde isadded, the procedure being otherwise the same as described in Example 2,then there are likewise obtained even dark-grey wool dyeings well dyedthroughout.

Said diphenyl-naphthyl-methane sulphonic acid may be obtained bycondensing 1 mol naphthalene and 0.1 to 3 mols ofdiphenylpolymethylenechloride dissolved in 1 to 3 mols of sulphuric acidat a temperature of 100° to 180° and neutralization of the acid withaqueous sodium hydroxide solution.

If, instead of the dyestuff given in Example 2, 0.6 g of the dyestuff ofthe formula ##STR3## or 0.6 g of the dyestuff of the formula ##STR4## isused, in procedure being otherwise as described in Example 2, then thereis obtained a red wool dyeing well dyed throughout and possessingfastness to light and to wet processing.

EXAMPLE 3

An amount of 1.3 g of the dyestuff of the formula ##STR5## is dissolvedin 90 ml of hot water; additions are then made to the solution of 0.5 gof the disodium salt of di-(6-sulphonaphthyl-2)-methane, 0.05 g ofnonylphenol decaglycol ether and 0.5 g of sodium sulphate, and theliquor made up to 100 ml by the addition of water. After cooling to roomtemperature, the dyestuff solution is transferred together with 66.6 gof cotton fabric to a metal container such as is described in Example 1.With otherwise the procedure as given in Example 1, there is obtained anevenly dyed dark-grey cotton fabric which is well dyed throughout andpossesses good fastness to wet processing and to light.

If, instead of 0.5 g 0.2 g of the disodium salt ofdi-(6-sulphonaphthyl-2)-methane or 0.3 g of the condensation product of2 mols diphenyl-naphthyl-methane sulphonic acid and 1.1 mols offormaldehyde are used in the above example, the procedure beingotherwise as described in the example, then there is likewise obtainedan even dark-grey dyeing on cotton fabric well dyed throughout.

EXAMPLE 4

An amount of 0.66 g of the dyestuff of the formula ##STR6## is dissolvedin 90 ml of hot water. Additions are made to the obtained solution of0.5 g of the disodium salt of di-(6-sulphonaphthyl-2)-methane and 0.2 mlof 80% acetic acid, and the solution is then made up by the addition ofwater to 100 ml. After cooling to room temperature, the dyestuffsolution is transferred, together with 66.6 g of a polyacrylonitrilestaple fabric (ORLON) in the rolled-up state, to a metal container suchas is employed for the dye baths of the equipment of the firm Callebautde Blicquy, Brussels; the container is thereupon sealed and thoroughlyshaken. The container is then maintained in continuous movement in thedyeing apparatus in the usual manner; the bath temperature is raisedwithin 15 minutes from 20° to 100°, and then held at this temperaturefor 30 minutes. After cooling, the dyed fabric is removed, and thensqueezed out to leave as little moisture as possible in the material; itis subsequently rinsed by heating with water, with a goods to liquorratio of 1:2, in the above described container for 5 minutes, andfinally dried.

An even blue dyeing is obtained which is excellently dyed throughout,and which has very good fastness to wet processing and to light.

EXAMPLE 5

An amount of 0.66 g of the dyestuff of the formula ##STR7## is dispersedin 50 ml of hot water; additions are then made to the dispersion of 0.5g of the disodium salt of di-(6-sulphonaphthyl-2)-methane, and 0.6 g ofcarrier consisting of 45 parts of o-phenylphenol, 41 parts of ethyleneglycol, 2.5 parts of polyvinyl alcohol, 2.5 parts ofdioctylsulphosuccinate and 9 parts of water, dissolved in 50 ml of hotwater. After cooling to room temperature, the dyestuff suspension istransferred, together with 33 g of polyethylene glycol terephthalatefabric, to a metal container such as is described in Example 1. If theprocedure given in Example 1 is then carried out, an even orange dyeingwell dyed throughout is obtained, which possesses the same fastness towet processing and to light as a corresponding dyeing on polyethyleneglycol terephthalate fabric obtained in the usual manner with a goods toliquor ratio of 1:10.

EXAMPLE 6

If, instead of the dyestuff given in Example 1, 0.01 g of the opticalbrightener of the formula ##STR8## is used, the procedure beingotherwise as described in Example 3, then there is obtained an evenoptically brightened cotton fabric.

EXAMPLE 7

An amount of 0.66 g of the dyestuff mixture consisting of 10 parts ofthe dyestuff of the formula ##STR9## and 60 parts of the dyestuff of theformula ##STR10## is dissolved in 90 ml of hot water; additions are thenmade to the dispersion of 0.5 g of the disodium salt ofdi-(6-sulphonaphthyl-2)-methane and 0.2 ml of acetic acid (80%), and thedispersion made up to 100 ml by the addition of water. The dyestuffdispersion is cooled to room temperature and transferred, together with66.6 g of a mixed fabric in the rolled-up state, consisting of 67% ofpolyethylene glycol terephthalate and 33% of wool, to a metal container;the container is sealed and well shaken. The container is then kept incontinuous movement, in the usual manner, in the dyeing apparatuscorresponding to Example 1; the bath temperature is raised within 15minutes from 20° to 130° and this temperature maintained for 30 minutes.After cooling, the mixed fabric is removed; it is squeezed out to about50% moisture content; it is subsequently rinsed with cold water, andthen soaped with warm water containing 2 g/l of the addition product of9 mols of ethylene oxide with 1 mol of nonylphenol.

An even navy blue dyeing well dyed throughout is obtained, with bothfibre constituents being uniformly dyed.

EXAMPLE 8

An amount of 10 g of the dyestuff of the formula ##STR11## is dissolvedin 1500 ml of hot water; additions are then made to the solution of 10 gof the disodium salt of di-(6-sulphonaphthyl-2)-methane and 20 ml ofacetic acid (80%), and the whole made up by the addition of water to2000 ml. After cooling to room temperature, the dyestuff solution issprayed in atomised form by means of a volumetric gear under a pressureof 25 atmospheres to pullovers rotating continuously in a drum at roomtemperature with a rotary speed of 25 revolutions per minute, the saidpullovers being made from polyamide-6.6 and having a total weight of1000 g. After completion of the atomisation spraying process, theindirect heating is switched on, with the drum still rotating, and byaddition of 1000 ml of water to the bottom of the drum and evaporationof the water, an immediate formation of saturated steam in the drum isobtained, whilst the temperature is allowed to rise to 98°. Within 10minutes there is produced in this manner a saturated steam atmosphere of98° and this then maintained for 20 minutes. The dyed material issubsequently cooled to a temperature of 70° and then centrifuged in thedyeing drum until a residual moisture content of about 50% on the fibreis obtained. An amount of 2000 ml of water is thereupon applied byatomisation to the rotating dyed textile material. After completion ofthis atomisation washing treatment, the dyed material is centrifuged andafterwards dried with hot air at about 100°.

An even, non-streaky, brilliant red dyeing is obtained on pullovers madefrom polyamide-6.6 well dyed throughout and possessing good fastnessproperties.

EXAMPLE 9

An amount of 1.3 g of the disodium salt of copper phthalocyaninedisulphonic acid is dissolved in 90 ml of hot water; additions are thenmade to the solution of 0.5 g of the disodium salt ofdi-(6-sulphonaphthyl-2)-methane and 0.8 g of sodium sulphate, and theliquor made up to 100 ml by the addition of water. After cooling to roomtemperature, the dyestuff solution is transferred together with 66.6 gof cotton fabric to a metal container such as is described in Example 1.With otherwise the procedure as given in Example 1, there is obtained anevenly dyed turquoise cotton fabric which is well dyed throughout andpossesses good fastness to wet processing and to light.

We claim:
 1. A batch process for dyeing fiber material comprising thesteps of first applying to the fiber material a non-thickened aqueousdye liquor, consisting essentially of(a) a water-soluble orwater-dispersible dyestuff having affinity for the fiber material (b)0.2 to 10 g/l of a non-foaming anionic dispersing agent selected fromthe group consisting of benzene monosulfonic acid, naphthalenemonosulfonic acid, C₁ -C₄ -alkyl benzene monosulfonic acid, C₁ -C₄-alkyl naphthalene monosulfonic acid, tetrahydro naphthalene sulfonicacid, dinaphthylmethane disulfonic acid, diphenyl-naphthylmethanesulfonic acid, a 2:1 to 2:2 adduct thereof with formaldehyde, andwater-soluble salts thereof, and (c) water,at a goods-to-liquor ratio of1:1.5 to 1:2.5 and at a temperature below the absorption temperature ofthe dyestuff, subsequently in a closed container subjecting the fibermaterial and applied aqueous dye liquor to shaking or tumbling in arotating drum sufficient to distribute evenly the aqueous dye liquor onthe fiber material while still maintaining the temperature below theabsorption temperature of the dyestuff, and finally heating the fibermaterial and the evenly distributed aqueous dye liquor to exhaust thedyestuff onto the fiber material.
 2. The process of claim 1, wherein thedispersing agent is used at a concentration of 2 to 5 g/l.
 3. Theprocess of claim 1, wherein the dispersing agent is a formaldehydeadduct of benzene monosulfonic acid, naphthalene monosulfonic acid, C₁-C₄ -alkyl benzene monosulfonic acid, C₁ -C₄ -alkyl naphthalenemonosulfonic acid, β-tetrahydro naphthalene sulfonic acid, dinaphthalenemethane disulfonic acid, or diphenyl naphthalene methane sulfonic acid,having an arylformaldehyde ratio of 2:1.1 to 2:1.2, or a water-solublesalt thereof.
 4. The process of claim 1, wherein the dispersing agent isthe disodium salt of di-(6-sulfonaphthyl-2)-methane.
 5. The process ofclaim 4, wherein the dispersing agent is used at a concentration of 2 to5 g/l.
 6. The process of claim 1, wherein the aqueous dye liquor andfiber material is heated in the final step at a temperature in the rangeof 95° to 140° C.
 7. The process of claim 6, wherein the heating iseffected by the introduction of saturated steam, super heated steam, orhot air.
 8. The process of claim 1, wherein the fiber material andapplied aqueous dye liquor are shaken or tumbled in a rotating drum toevenly distribute the aqueous dye liquor on the fiber material.